The purpose of this K23 proposal is to prepare the candidate to become an independent investigator, able to design, acquire funding for, and perform valid clinical trials in children with co-occurring neurologic and psychiatric disorders. The candidate proposes a unique and well- integrated combination of educational experiences: 1) mentorship with established clinical trials researchers in psychiatry, neurology, and outcomes research; and 2) a rigorous master's training program in statistics and research design, with 30 hours of classroom time per month over 18 months. The candidate proposes to implement the lessons learned in a clinical effectiveness trial of multi-drug treatments in children and adolescents with Tourette's Syndrome, a paradigm disorder of co-occurring neurologic and psychiatric symptoms. Tourette's Syndrome is a neuropsychiatric disorder characterized by greater than one year of motor and vocal tics that are functionally or socially disturbing. Children and adolescents frequently have multiple co-occurring neuropsychiatric diagnoses and are treated with combinations of medications that have never been tested together. Current clinical research typically involves efficacy studies of monotherapy that may have limited clinical relevance. The research proposal of this K award includes a randomized controlled clinical effectiveness study of a dopamine agonist, pergolide, allowing for concurrent treatment of comorbid disorders. The primary hypothesis is that treatment with pergolide will be associated with significant tic suppression, independent of concurrent treatment for OCD or ADHD. The study will have the power to determine whether the presence of treated co-morbid OCD or ADHD accounts for significant variance in the change in tic symptoms on medication. An additional focus of the grant will be developing measures of health care utilization and costs in this disorder and determining their relationship to the presence of absence of effective symptom management.